VOLUME ATTRIBUTES

VOLUME ATTRIBUTES ( volume ; size ; used ; free )

Parameter	Type		Description
volume	Text	→	Volume name
size	Real	←	Volume size expressed in bytes
used	Real	←	Used space expressed in bytes
free	Real	←	Free space expressed in bytes

Description

The VOLUME ATTRIBUTES command returns, expressed in bytes, the size, the used space and the free space for the volume whose name you pass in volume.If volume indicates a non-mounted remote volume, the OK variable is set to 0 and the three parameters return -1.

Example

Your application includes some batch operations running the night or the week-end that store huge temporary files on disk. To make this process as automatic and flexible as possible, you write a routine that will automatically find the first volume whose free space is sufficient for your temporary files. You might write the following project method:

  // Find volume for space Project Method
  // Find volume for space ( Real ) -> String
  // Find volume for space ( Space needed in bytes ) -> Volume name or Empty string
 
 C_STRING(31;$0)
 C_STRING(255;$vsDocName)
 var $vlNbVolumes;$vlVolume : Integer
 var $1;$vlSize;$vlUsed;$vlFree : Real
 var $vhDocRef : Time
 
  // Initialize function result
 $0:=""
  // Protect all I/O operations with an error interruption method
 ON ERR CALL("ERROR METHOD")
  // Get the list of the volumes
 ARRAY STRING(31;$asVolumes;0)
 gError:=0
 VOLUME LIST($asVolumes)
 If(gError=0)
  // If running on windows, skip the (usual) two floppy drives
    If(On Windows)
       $vlVolume:=Find in array($asVolumes;"A:\\")
       If($vlVolume>0)
          DELETE FROM ARRAY($asVolumes;$vlVolume)
       End if
       $vlVolume:=Find in array($asVolumes;"B:\\")
       If($vlVolume>0)
          DELETE FROM ARRAY($asVolumes;$vlVolume)
       End if
    End if
    $vlNbVolumes:=Size of array($asVolumes)
  // For each volume
    For($vlVolume;1;$vlNbVolumes)
  // Get the size, used space and free space
       gError:=0
       VOLUME ATTRIBUTES($asVolumes{$vlVolume};$vlSize;$vlUsed;$vlFree)
       If(gError=0)
  // Is the free space large enough (plus an extra 32K) ?
          If($vlFree>=($1+32768))
  // If so, check if the volume is unlocked...
             $vsDocName:=$asVolumes{$vlVolume}+Char(Directory symbol)+"XYZ"+String(Random)+".TXT"
             $vhDocRef:=Create document($vsDocName)
             If(OK=1)
                CLOSE DOCUMENT($vhDocRef)
                DELETE DOCUMENT($vsDocName)
  // If everything's fine, return the name of the volume
                $0:=$asVolumes{$vlVolume}
                $vlVolume:=$vlNbVolumes+1
             End if
          End if
       End if
    End for
 End if
 ON ERR CALL("")

Once this project method is added to your application, you can for instance write:

 $vsVolume:=Find volume for space(100*1024*1024)
 If($vsVolume#"")
  // Continue
 Else
    ALERT("A volume with at least 100 MB of free space is required!")
 End if

See also

VOLUME LIST

Properties

Command number	472
Thread safe	✓
Modifies variables	OK, error